3. Single Celled Organisms

1. Note: This lesson is assessed in the Microscope Internal but not the External Exam 3. Single Celled Organisms Describe the structure of a variety of single celled organisms and the functions of their organelles

2. Unicellular Organisms -Unicellular (one celled) organisms are good models for membrane transport, because they need to perform many functions with one cell, rather than many types of cells.

3. Unicellular organisms possess a high degree of complexity for one cell. Note: multicellular organisms have many cells, but each type performs one basic function. The interaction of the cells allows a multi-celled organism to live.

4. There are 3 main types of unicellular organisms • Euglena • Paramecium • Amoeba • You will be given diagrams of these three organisms. • Use the slides following to label and take notes about the functions of their organelles.

5. Some Common Unicellular Organisms • Euglena: a genus of microscopic • organisms in the Protista Kingdom. -lives in fresh water, and are especially common in warm seasons, when they populate drainage ditches and ponds.

7. -Euglena has a spindle-shaped body, and range in size from 1/1000 to 1/100 of an inch (0.025 to 0.254 mm) long. -Most species are green, because they contain chloroplasts, which allows them to produce their own food. They serve as primary producers in many aquatic ecosystems.

8. -Some species also eat small particles of food. -moves via a flagellum, which is a whip- like appendage that sticks out of the body. -some Euglena also have a specialized “eye spot”, which serves as a light sensor, directing them toward available light.

9. Chloroplasts Flagellum

10. Euglena Hibernation/Reproduction Hibernation: when conditions are bad (dry or too hot/cold) Euglena forms into a sphere, called the palmelloid stage. Each euglena then discards its flagellum, and forms a mucus outer covering.

11. Euglena undergo reproduction called “binary fission” Each euglena first creates two of everything, then splits evenly into two halves.

12. 2) Paramecium: another genus of Protists, often called “slipper protists” because of their shape like a bedroom slipper. -usually less than 0.01 inches (.25mm) in length, and covered with very small hair like projections called cilia.

14. Cilia are used in movement, and during feeding. -Paramecium does NOT have chloroplasts so therefore is a strict consumer. -It eats small particles of food or bacteria from fresh water where it lives. The most common paramecium is Paramecium caudata, which is used for research

15. Paramecium Reproduction Paramecium have two ways to reproduce. • They can reproduce • Asexually, and split • into two (binary fission) This type of reproduction does NOT involve the swap of genetic material, and makes a clone of the parent.

16. 2) The second form of reproduction is called conjugation, and involves the paramecium swapping genetic material. This type of reproduction does not result in a clone, but an individual with a new set of genetic instructions. This will lead to genetic variation within the population of paramecium.

17. 3) Amoeba:one of the simplest of the protists. -Amoeba possess a very flexible cell membrane, and constantly moving cytoplasm. -moves by “pouring” cytoplasm into extensions of the cell membrane, called pseudopodia.

18. -the shape of the amoeba continually changes as new pseudopodia are created, and others disappear. Eats by surrounding its prey with pseudopods, and slowly engulfing it. This is called phagocytosis. http://www.youtube.com/watch?v=pvOz4V699gk

19. Amoeba Anatomy

21. 2 1 Pseudopods 3 4 Amoeba feeding sequence

22. New organelles • Contractile vacuoles – used to pump excess water out of the cells – they collect the water from the cytoplasm and excrete it through pores. • http://www.youtube.com/watch?v=mTXRcbjuYGU

23. Cilia – Hair like extensions of the cell membrane that contain microtubules. They are used to propel the organism throguh water in unicellular organisms.

24. Recap Quiz • Which organism is a producer? • Which organism moves by pouring cytoplasm into extensions of its body? • What is phagocytosis? • What does a paramecium feed on? • How do paramecium reproduce?